A mother and her boyfriend who violently abused a baby boy have been jailed over his death, police said.

Katherine Cox and Danny Shepherd were convicted of causing or allowing the death of four-month-old Eli Cox, after he succumbed to a catastrophic brain injury in April 2016.

Kent Police said a post-mortem examination revealed that his injuries were consistent with being vigorously shaken and hitting his head, along with 28 bone fractures, thought to have been inflicted over a 10-week period.

Cox, 33, and Shepherd, 25, formerly of Lapwing Close, Minster, in Kent, appeared at Maidstone Crown Court on Tuesday, where they were sentenced to eight years and 13-and-a-half years respectively, after previously being found guilty at an earlier hearing.

The couple are believed to have caused the child’s series of bone fractures in at least five separate incidents from February 2016 onwards, and officers said it would have been obvious to anyone responsible for his care that he was in pain.

Police said Eli was first taken to hospital on April 13 last year after he stopped breathing, and was found to have sustained bruises that were not thought to have been accidental.

He eventually died two weeks later, and further investigations revealed traces of cocaine and amphetamine in his system.

Cox and Shepherd both denied being users of either classified substance, despite officers from the Kent and Essex Serious Crime Directorate later finding five wraps of the latter in the family’s garden shed.

Detective chief inspector Ivan Beasley said: “The death of a child is never anything less than tragic, but the circumstances behind Eli Cox’s passing are especially upsetting for those of us who share a compassion for others.

“None of us will ever understand what compels people to cause harm to children, and it is unfortunately true to say that Eli suffered more than most and was robbed of his life before it had barely begun.

“Katherine Cox and Danny Shepherd maintained their innocence throughout, but the jury saw through their lies.

“Only they know the true extent of the abuse Eli was put through, which is simply unthinkable to most members of society including parents who would do anything to protect their children from harm.”